This would not be the kind of information that it would be appropriate to post to MobileRead.

Thank you.

There isn't anything illegal about changing the serial number of a motherboard, it's just that Amazon chooses not to support it because they'd rather sell you a new device than have you repair an old one. As far as illegalities go, removing the DRM from protected eBooks is a lot more "illegal" than changing the serial number of a Kindle motherboard.